Apparatus for improving spinnability and property of composite filament

ABSTRACT

Method and apparatus for spinning a composite filament wherein two polymers having different melt viscosities are melted separately and the temperature of each maintained so that the melt viscosity ratio of the molten polymers is 0.4 to 2.5 until extrusion. The apparatus includes means for controlling the temperatures of the two spinning melts separately and retarding transmission of heat between the melts until they are extruded together.

I United States Patent 1151 3,659,989 Uraya et a1. 1 51 May 2, 1972 54]APPARATUS FOR IMPROVING [56] References Cited SPINNABILITY AND PROPERTYOF COMPOSITE FILAMENT UNITED STATES PATENTS 2,931,091 41960 B ..188 [72]Inventors: Toru Uraya, Kobe C1ty; Shusuke 3,320,633 551967 2:2 at a]. SCx Kageyama, Osaka bmh Japan 3,197,813 8/1965 Le Grand 73 Assignee;Kanegafuchi Bosek] Kabushik] t 3,408,277 10/1968 Martin et a1. ..264/168Tokyo, Japan Primary Examiner-J. Spencer Overholser [22] Hedi June 1970Assistant Examiner-Michael 0. Sutton [21] APPL Nu: 47,862Attorney-Stevens, Davis, Miller and Mosher Related US. Application Data[57] ABSTRACT [63] Continuation of Ser, No. 568,016, July 26, 1966, Pat.M h n pp r f p nning a mp ite filament N 3 536,301 wherein two polymershaving different melt viscosities are melted separately and thetemperature of each maintained so [30] F rei n A li tion Prio it D tthat the melt viscosity ratio of the molten polymers is 0.4 to

2.5 until extrusion. The apparatus includes means for con- 1965 Japan"40/47078 trolling the temperatures of the two spinning melts separatelyJuly 15, 1966 Japan ..41/46271 and retarding transmission of heatbetween the melts until they are extruded together. [52] U.S.Cl..425/131,264/176F,425/199, 425/379 [51] Int. Cl. ..D01d 3/00 [58] Fieldof Search ..264/171 F, 168, 176 F; 7 Claims, 8 Drawing Figures 18/8 SM,8 SC PATENTEDMAY 2 I972 SHEET 16F 2 Fig.

Intrinsic viscosity [*1] APPARATUS FOR IMPROVING SPINNABILI'I'Y ANDPROPERTY OF COMPOSITE FILAMENT This application is acontinuation-in-part of our copending application Ser. No. 568,016,filed July 26, 1966, and now U.S. Pat. No. 3,536,802, issued Oct. 27,1970.

The present invention relates to a method and an apparatus for forming acomposite filament in which a plurality of different fiber-formingthermoplastic synthetic linear polymers are bonded eccentrically alongthe length of filament, in which said polymers are separately melted andthen spun simultaneously from the same orifice, wherein the spinnabilityis improved, and thus evennesses of the size of filament and theconjugate ratio of the component polymers along the length of thefilament and the production efiiciency are highly improved.

It has been well known that according to so-called conjugate spinningprocess," a plurality of fiber forming polymers having differentchemical and physical properties are fonned into a unitary filament inwhich these polymers are arranged eccentrically in any cross-section offilament and that the resulting filament develops spiral crimps whensubjected to a proper after-treatment, such as, heating of a treatmentwith a swelling agent, due to difference of thennal shrinkage orswelling property of the component polymers of the filament and someproposals have been already made and practised commercially.

However, in this field, heretofore investigations have not beensubstantially directed to spinnability in the spinning process butmainly to improvement of crimpability or crimp stability of theresulting filament and in the practical industrial production, and therehave been a number of difficulties in spinnability and drawbacks inproperties of the product and production efficiency. Namely, in order toprovide a high crimpability, for example, the following processes havebeen attempted, in one of which the same kinds of two polymersconsisting of the same monomer and having different average degree ofpolymerization are conjugate spun and in the other of which differentpolymers, copolymers or blend polymers having remarkably differentphysical properties, particularly, property in a molten state are spun.In these many cases, a bending phenomenon of unsolidified filamentimmediately after the extrusion is an important problem to be solved.

Such a bending phenomenon occurs remarkably when a plurality of polymersare bonded in a high eccentric relation in the cross section of filamentand particularly, when said polymers are arranged adjacently in a sideby side relation. When the bending phenomenon is very much, the bentpolymers immediately after extruded from orifice contact and adhere tothe spinneret surface and the spinning operation cannot be effected. Inthe specification of U.S. Pat. No. 3,176,342, there has been disclosed aspinneret in which in order to prevent the bent polymers from adhesionto the spinneret surface, orifice is protruded relatively to thesurrounding spinneret surface. Further more, in the specification ofBritish Pat. No.965,729 there has been disclosed a method in which inorder to project the polymers in perpendicular direction as far aspossible, two polymers having different melt viscosities are conjugatespun by using a spinneret provided with orifice, the central axis ofwhich is inclined against spinneret plate in opposite direction tobending direction of the polymers. However, the spinneret disclosed inthe aforesaid U.S. patent does not solve fundamentally the problem and afluctuation phenomenon and an unevenness of tension occur based on thebending of the filament, so that the conjugate ratio of the resultingcomposite filament is not even and the unevenness of the size offilament is brought about and therefore the property of the product isconsiderably deteriorated. Moreover, in order to prevent increase of thebending phenomenon, it is impossible to increase considerably thespinning velocity, while it is necessary to maintain the distancebetween orifices in the spinneret surface sufficiently large to preventbent spun filaments from contact each other, so that the spun amount perunit area of the spinneret plate is considerably limited and theproduction efficiency is affected adversely.

Furthermore, the method described in the aforesaid British patent hassome disadvantages, in which a suitable spinneret plate must be selecteddepending upon the kind of polymers, the direction for feeding thepolymers to the spinneret can not be changed and the manufacture of thespinneret plate is rather ditficult.

After deliberate investigations with respect to interrelation betweenphysical property of the starting polymers, the bending phenomenon,adhesion to spinneret and properties of the resulting filament, theinventors have found that the above described troublesome bendingphenomena depend upon mainly difference of viscosity of different moltenpolymers and when the difference of viscosity is remarkable, the meltsextruded from the orifice after combined and bonded in the spinneret arebent to the side of the polymer having higher viscosity and that ifratio of the melt viscosities in spinning temperature of the bothpolymers is more than 3.0, the melt adheres to the spinneret surface andthe spinning operation can not be effected. The invention isaccomplished based on investigation with respect to an importantcorelation between the melt viscosity of the polymers and the bendingphenomena.

An object of the invention is to provide a novel method for conjugatespinning a plurality of fiber forming thermoplastic synthetic linearpolymers, wherein said bending phenomena in the extruding stage arereduced to a minimum and the spinning operation is carried out smoothlyin a high efiiciency. A further object of the invention is to provide acomposite filament having latent crimpability and highly improvedevenness of the size of filament and conjugate ratio of the componentpolymers along the length of filament.

A further important object of the invention is to provide an improvedspinneret for carrying out the above mentioned method.

The other object will be illustrated in more details by the followingdescription.

The method of the present invention is characterized in that when twofiber forming thermoplastic synthetic linear polymers having differentmelt viscosities in each optimum spinning temperature are separatelymelted and then extruded simultaneously from the same orifice to form aunitary filament in which these polymers are bonded eccentrically alongthe length of filament, the melt viscosities of said two polymers areregulated independently prior to extrusion of the molten polymers tokeep the ratio of melt viscosity of said two copolymers within the rangeof from 0.4 to 2.5 and then the molten polymers are extruded.

With respect to relation between melt viscosity of thermoplasticsynthetic linear polymer and its temperature and degree ofpolymerization, the following equation has been proposed by PJ. Flory.Namely, the melt viscosity is p, absolute temperature T, and an averagemolecular weight 2 and they have the following relation:

log A B/T+ C(Z)" wherein, A, B and C are constants and B is temperaturecoefficient, C degree of polymerization coefficient and A a constant ofsubstance relation to melting point, etc.

The Flory's equation for melt viscosity is applied properly toconventional fiber fonning thermoplastic synthetic linear polymers, suchas, polyamide, polyester, polyolefin, and etc., within a range oftemperature suitable for spinning and it shows that melt viscosity ofpolymer varies depending upon the kind of polymers,that the meltviscosity decreases as the temperature increases in a homologous seriesof polymers and that it increases as the average degree ofpolymerization, that is, intrinsic viscosity increases.

For example, the relation between intrinsic viscosity (1 ofpolycapramide and melt viscosity at each temperature obtained from theresults of experiments is shown in FIG. 1. The term intrinsic viscosity"used herein means one defined by the following equations wherein h9 7 701 1; viscosity of a solution of a polymer dissolved in m-cresol at 30 C.1 viscosity of pure m-cresol at 30 C. C 1 Concentration of the polymerin g./ 100 cc. of the solution. The limiting value of C is extrapolationof found values of various concentrations of C= 0.1, 0.2, 0.3, 0.4 and0.5 percent to C 0.

In polyamide to be used for sample, water soluble components areextracted sufficiently by a conventional process and then the resultingpolyamide is dried to control the water content to less than 0.1percent. The dried polyamide is dissolved in mcresol having purity ofmore than 90 percent and the resulting solution is heated at atemperature from 95 C to 100 C for at least 4 hours to dissolve thepolyamide sufficiently and then the solution is filtered. The viscosityof the resulting solution is determined by a conventional method bymeans of Ostwalds viscosimeter.

As shown from the diagram illustrated in FIG. 1, such above mentionedrelation that if the value of intrinsic viscosity of polymer (1increases, the value of melt viscosity at the same temperature alsoincreases and in the polymers having the same intrinsic viscosity themelt viscosity decreases as temperature increases, can be proved. Thesimilar diagrams can be obtained experimentarily with respect to otherthermoplastic synthetic linear polymers, such as polyester, polyesterether, polyolefin and etc. or the copolymers, but with reference topolyamide, particularly, polycapramide the illustration will be madehereinafter for the convenience of the illustration.

Filament obtained by a conjugate spinning process in which two kinds ofpolycapramides having different number average degree of polymerization,that is, intrinsic viscosities are bonded eccentrically alonglongitudinal direction of filament develops spiral crimp by heattreatment due to difference of shrinkage ratio in hot water ofpolycapramides composing said filament. In this case, in order todevelop an excellent crimp it is necessary that the difference ofintrinsic viscosities of the both polyamides is at least 0.20,preferably, at least 0.25. However, these polycapramides having such alarge difference of intrinsic viscosities have remarkable differencealso in the melt viscosity at the same optimum spinning temperature, sothat the spinning operation cannot be smoothly effected by aconventional method due to the bending phenomena. For example, the meltviscosities of polycapramides having intrinsic viscosity of 0.95 and1.15 at 250 C are 800 and 1,100 poises respectively and when thesepolycapramides are conjugate spun in the side by side type throughspinneret of 0.3 mm of dia. at 250 C in an extruded amount of 7.5 g/min.respectively at a take-up velocity of 600 m/min., the polymers areinclined by about 45 in the outlet of the orifice and the freshly spunfilament is considerably uneven both in size and conjugate ratio.Furthermore, melt viscosities of polycapramides having intrinsicviscosity of 0.95 and 1.20 are 800 and 2,600 poises respectively, and inthis case, the spun polymers adhere to the spinneret surface as soon asthe spinning starts and the spinning operation cannot be effected. Thenif the melt temperature of a polymer having lower melt viscosity, thatis, a polymer having intrinsic viscosity of 0.95 is maintained at 250 Cand the melt temperature of a polymer having higher melt viscosity, thatis, a polymer having intrinsic viscosity of 1.20 is increased to 265 C,the bending phenomenon is considerably improved and in a temperature of280 to 285 C this phenomenon can be solved to a substantially negligibleextent and the extruded amount and the take-up velocity can be increasedto l .5 times as compared with the case of 265 C.

The term the optimum spinning temperature" used herein means usually atemperature within the range from about 20 to 50 C higher than themelting point of the polymer, although it varies more or less dependingupon the kind of thermoplastic synthetic linear polymer and it must bedetermined considering difference of melt viscosity due to difference ofintrinsic viscosity and thermal stability of the polymer and the like.In the invention, a temperature about 35 C higher than the melting pointof the polymer is defined as the optimum spinning temperature.

If the spinning temperatures in extrusion of two kinds of spinningmaterials having diflerent melt viscosities at the optimum spinningtemperature are adjusted independently and said materials are spunsimultaneously from the same orifice at substantially the same meltviscosity, the above described bending phenomenon does not occurentirely, which is an ideal embodiment for carrying out the method ofthe invention into effect.

However, sometimes the melt viscosities at the optimum spinningtemperature are considerably different according to the kind of thepolymer to be used and if the temperature is increased extremely inorder to remove the difierence, the decomposition and foaming of thepolymer are generated and in the worst case, coloring and carbonizationand the like occur, and the workability and the properties of the fiberare damaged, so that such an increase of temperature must be avoided.

Concerning these problems, the upper limit of the melt temperature is atemperature 150 C higher than the melting point of the polymer,preferably, a temperature C higher than the melting point, although theupper limit varies depending upon the kind of polymer and the time formaintaining the temperature condition. Accordingly, in practice, it issometimes difficult to obtain the above described ideal condition forpractice and if the ratio of melt viscosity of both polymers is 0.40 to2.50, preferably, 0.50 to 2.00, most preferably, 080 to 1.25, the objectof the invention can be attained. However, if the ratio of meltviscosity exceeds the above range, the spinning operation may be carriedout attending many bending phenomena, although the strength, elongation,Youngs Modulus, size and conjugate ratio of the resulting compositefilament are uneven and satisfactory results can not be obtained.

Although in the method of the invention, it can be effected in variousstages prior to extrusion that the polymer having higher melt viscosityis further heated solely, in any case it is necessary to avoidsubstantially transmission of heat of the both polymers. Such a heatingcan be carried out fustly in an apparatus for melting polymers. However,since in the melting apparatus, the staying time of the polymers in themolten state is longer, it should be avoided to keep the polymers undera temperature fairly higher than the optimum spinning temperature for along period in order to prevent the decomposition, foaming, degradationor coloring of the polymers during such a time. In view of such a point,it is most preferable that the molten polymers in the melting apparatusare retained at the optimum spinning temperature proper to the polymersirrespective of the melt viscosity of each polymer and transferred tothe spinneret, after which the polymer having higher melt viscosity isheated immediately in such a manner that the melt viscosities of theboth polymers are near or same in the spinneret before extrusion of saidpolymer. However, if the temperature enough to bring about the ratio ofmelt viscosity of the both polymers to the desired value does not exceedthe above described range of the optimum spinning temperature proper tothe polymer, that is, the range of 20 to 50- C higher than the meltingpoint and the decomposition, foaming and the other problems do notsubstantially occur even if such a temperature is retained for fairlylong period, it is sufficient to set melt temperatures in the meltingapparatuses suitably, whereby the melt viscosities of the both polymersare previously brought about to each desired value and then to controlthe temperatures so as to keep each temperature as it is in thespinneret. This adjustment and control of temperature can be easilycarried out by using the spinneret according to the present invention asmentioned hereinafter.

In the above mentioned specific illustration, although there wasmentioned a case wherein two kinds of polycapamide having differentintrinsic viscosities are conjugate spun in a side by side type, themethod of the invention can be applied to a combination of homologouspolymers, for example, a combination of the same kind of polyestershaving different intrinsic viscosities, a combination of the same kindof polyolefins having different melt indexes; a combination of differentkinds of homopolyamides, such as, polycapramide/polyhexamethyleneadipamide, polycapramide/polyhexamethylene sebacamide, polyhexamethyleneadipamide polyaminoundecanoic acid; a combination of homopolyester andhomopolymester ether, such as polyethyleneterephthalate/polyethyleneparaoxybenzoate; a combination ofhomopolyolefins, such as polyethylene having a high density/polyethylenehaving a low density, polyethylene having a high density/isocacticpolypropylene; a combination of homologous homopolymer and copolymer,such as polycapramide/polycapramide-polyhexamethylene isophthalamidecopolymer, polyhexamethyleneadipamide/polyhexamethyleneadipamide-polyhexamethylene terephthalamide copolymer, polyethyleneterephthalate/polyethylene terephthalate-polyethyleneisophthalatecopolymer; a combination of different kinds of polymers, such as,polyamide/polyester, polyester/polyolefin,polyamide/polyolefin,polysulfonamide/polyurea, polyamide/polyolefin, polyvinylchloride/polyvinylidene chloride. Furthermore, thermoplastic syntheticlinear polymers, such as polyurethane, polyoxymethylene,polypivalolactone and polychlorotrifluoroethylene can be used properlyby combining with the above mentioned various kinds of polymers.Further, besides the copolymers, graft polymers and mixtures thereof orthe above described polymers added with viscosity stabilizer, dyestuff,pigment, plasticizer and other organic or inorganic additives can, ofcourse, be used.

Although according to a suitable combination of these polymers, theoptimum spinning temperatures of the two spinning materials may besubstantially the same and said two spinning materials may showsubstantially the same melt viscosity in such a temperature, the methodof the invention can be advantageously applied in order to improve thespinning condition, spinnability and properties of filament except sucha case. Namely, even if the ratio of melt viscosity of the two polymersto be used at the same temperature is within the range of from 0.4 to2.5, it is very effective to approach the ratio to 1.0 according to thepresent method. By such a means the bending phenomenon of the spun meltin the conjugate spinning is suppressed to minimum or solved entirelyand the two kinds of polymers can be smoothly spun with an extremelyexcellent arrangement without attending fluctuation phenomenon andunevenness of tension, so that a composite filament of excellentproperties having extremely even size of filament and a constantconjugate ratio along the length of filament and having no unevenness instrength, elongation and Youngs Modulus can be produced.

Furthermore, the conjugate state of the two kinds of fiber formingpolymers according to the present method may be an arrangement in whichsaid polymers are bonded in a side by side relation along the filamentaxis or an arrangement in which said polymers are bonded in a eccentriccore and sheath relation. In these cases, the conjugate ratio can bevaried properly.

Moreover, the composite filament obtained by the present method may benon-circular as well as circular in the cross section.

The improved spinneret to be used for practice of the present methodcomprises two filter blocks provided with solution reservoirs connectingto separate tubes for transferring the spinning solutions, a nonle plateprovided with at least one orifice, a breaker plate provided betweensaid filter block and said nozzle plate and provided with two channelsto introduce two spinning solutions fed from said solution reservoirs tothe rear of the same orifice separately, means for controlling thetemperatures of two kinds of spinning solutions separately and heatinsulators for preventing transmission of heat between the spinningsolutions.

For a better understanding of the invention, taken to the accompanyingdrawings, wherein FIG. 1 is a diagram showing a relation of intrinsicviscosity to melt viscosity at the melting temperature;

FIG. 2 is a vertically sectional view illustrating an embodiment of theapparatus according to the present invention;

FIGS. 3 and 4 are cross-sectional views taken along lines A-A and BB ofFIG, 2, respectively;

FIG. 5 is a vertically sectional view illustrating an alternateembodiment of the invention;

FIGS. 6 and 7 are cross-sectional views A-A and 8-8 of FIG. 5,respectively; and

FIG. 8 is an enlarged vertically sectional view illustrating the part ofspinneret shown in FIG. 5.

Referring to the drawings, the spinneret according to the inventioncomprises four main parts, that is, feeding block I, filter block II,breaker plate Ill and nozzle plate IV. The feeding block I is providedwith tubes 3 and 3' for transferring the spinning solutions which areconnected to melting apparatus through measuring pump (not shown). Twokinds of spinning solutions in heated and molten state are fedcontinuously to the solution reservoirs 2 and 2' in the filter block IIthrough the tubes 3 and 3 respectively. The spinning solutions, afterfiltered through filter 4 and 4' consisting of usually, gauze and finelydivided quartz and provided in the solution reservoirs 2 and 2' areintroduced into spaces between channels 5 and 5' provided beneath thebreaker plate Ill and upper face of the nozzle plate IV and are combinedat the rear 6 of the orifice 7 provided in the nozzle plate IV andbonded in an adjacent type and then extruded from the orifice 7.

The tubes 3 and 3 for transferring the spinning solutions and thesolution reservoirs 2 and 2' are insulated thermally by heat insulators8 and 9 respectively. It is preferable to insert a heat insulator 10 inthe center portion of the breaker Ill. The heat insulator is mouldedinto block having suitable thickness with a known heat insulator, suchas glass fiber of high silicate glass, asbestos and diatomaceous earthand glass fiber and asbestos are particularly preferable. lt ispreferable to provide one or more rows of ventilating holes 13 in theheat insulators, through which a gas having proper temperature andpressure is passed during a long period of spinning operation to improvethe effects for maintaining the temperature and insulating heat.

The feeding block I, the filter block II, the breaker plate I and thenozzle plate IV are connected through packings respectively and theassembly is heated by a proper means from the periphery thereof, wherebythe temperatures of the spinning solutions in the passages for thespinning solutions including the solution reservoirs are heated ormaintained at the proper given temperatures. The heating is effected byheating apparatuses to heat two clocks separated by the aforesaid heatinsulators 8 and 9 independently so as to keep the two spinningsolutions at different temperatures respectively. In the drawings, 11and 11 are independent electric heaters respectively and said heatersare provided with terminals 12 and 12' at the lower part, wherebyelectric currents are fed from the outer part. It is preferable that apart of lower portion of each electric heaters is inserted intointermediate portion of the nozzle plate 4 in order to control thetemperature at the surface of the nozzle plate easily and to prevent thethermal loss.

It is very easy and advantageous that the heating is effected by jacketsfor circulating a heat medium, such as DOWTHERM in addition to the abovedescribed electric heater. The control of temperature in the heatingmeans can be effected by a proper conventional automatic temperatureregulator.

The nozzle plate IV is provided with one or more of orifices 7. Theposition of the orifices is usually selected in such a manner that thelengths of courses of the channels 5 and 5' of reference is taken alonglines the breaker plate Ill are same, but it is possible to producemultifilarnent in which the optimum conjugate ratios of the two kinds ofpolymers between every spun filament are varied respectively bydeviating more or less each position of the orifices.

The assembly of the spinneret is further intercepted from the outertemperature by means of column for maintaining temperature (not shown).

in the spinneret of the other embodiment of the invention shown in FIGS.to 8, the spinning solution fed through the filter 4 from the solutionreservoir 2 is extruded from the orifice 7 through the channel 5provided in the lower part of the breaker plate [I]. On the other hand,the other spinning solution fed through the filter 4 from the solutionreservoir 2' to the breaker plate H1 is introduced into the innerorifice 1 through the channel 5 provided on the upper surface of thebreaker plate. As shown in FIG. 8 the central axis of the inner orifice1 is in an eccentric relation to the central axis of the orifice 7, sothat the spinning solution extruded from the inner orifice 1 issurrounded eccentrically by the other spinning solution to form a coreand sheath type of composite filament. in this embodiment, the means forheating is effected by heating media 14 and 14' circulating inindependent jackets 11 and ill. The medium for heating, for example,liquid or gaseous Dowtherrn is previously adjusted to a giventemperature and then introduced into the jacket and circulated in it.The above described spinneret is particularly, suitable for spinningcomposite filament having an eccentric core and sheath relation, so thatit is effectively used when the spinning materials consisting of acombination of completely different polymers having no mutual adhesiveproperty are selected.

Since the spinneret according to the present invention comprises meansfor controlling separately the temperatures of two spinning solutionsand the heat insulators for preventing each spinning solution fromtransmission of heat, a specific function which has never been attainedby a known spinneret, that is, a specific effect and function, by whichthe melt temperatures of two spinning solutions in the spinneret forconjugate spinning are adjusted and controlled independently andoptionally respectively, can be obtained. Moreover, the spinneret isused most advantageously in the practice of the method of the inventionand it is possible to provide a large number or orifices with a smallerdistance than that of the conventional one due to the fact that thebending phenomenon of the filament in the spinning is solved, so thatthe spinning velocity can be increased and also the extruded amount perunit area of the spinneret can be increased to at least 1.5 times theconventional process, whereby the production efficiency is increased andthe production cost is decreased.

Thus, according to the method of the invention and the apparatusthereof, the composite filament having an excellent spinnability andimproved properties can be easily produced and this filament can beutilized in a broad and commercial field, such as various commercialarticles, for example, various clothes, unwoven fabrics, felts, filtercloths, packings, base cloths for artificial leathers or interiordecorations, for example, carpets, curtains, bed clothes. Moreover, thecomposite filament obtained by the invention can be used as continuousfilaments or cut fiber and also can be used in mix-spinning ormix-weaving with the other synthetic or natural fibers. This compositefilament provides crimped filament having highly homogeneous crimp bysubjecting this filament to conventional crimping treatments, such asheat treatment and swelling treatment. The treatment for developingcrimp can be carried out in any step before or after production of theabove described articles.

Although in the above described illustration, the production of thecomposite filament consisting of two kinds of spinning materials wasdescribed, when conjugate spinning three or more spinning materials themethod and the apparatus according to the invention can be easilymodified within the scope of the invention.

The melt viscosity of the thermoplastic synthetic linear polymer can bedetermined by various measuring methods, such as falling sphereviscosimeter, capillary viscosimeter and rotational viscosimeter.However, in many cases, the value varies depending upon the measuringmethod, so that it is necessary to determine the melt viscosity by thesame measuring method. All the melt viscosities described in thefollowing examples were determined by the capillary viscosimeter method.Furthermore, the determination of unevenness of size of filament wasmade by Uster C type made by Zellweger Co., Switzerland.

A crimpability in hot water and load value for 50 percent shrinkage ofthe composite filament are determined as follows:

Each length of 30 samples having about 25 cm of length is determined andthe length is expressed by l. Such samples are immersed in boiling waterat C under no load for 10 minutes to develop crimp and then dried in airand the length of the dried samples is expressed by l,. Thereafter thesamples are suspended perpendicularly by 0.3 g/d of load at one end toremove the crimp and the length of the samples is expressed by 1 Thenthe crimpability in hot water can be shown by the following equation:

Crimpability (percent) L; 1 /0 X 100 This crimpability was determined byaverage value of the found values of 30 samples. Furthermore, thelengths, when applied various loads to this crimped filament are plottedto the load and the load value (mmg/denier) corresponding to length of50 percent shrinkage was determined from the graph. This value wasreferred to as the load value for 50 percent of shrinkage.

The invention will be illustrated more in detail with reference to thefollowing examples:

EXAMPLE 1 TABLE 1.

Heating Condition (C.)

Determined Portion Nylon 6 Nylon 66 Preheating portion 210 220 ExtruderMelting portion 260 285 I 5 cylinder Measuring portion 25 5 286 1 6Adaptor 257 285 2 5 Transferring tube 255 287 Spinneret head 260 287Nozzle plate surface 260 280 TABLE 2.

Spinning and Drawing Condition Number of revolution of extruder 20 screw(r,p.m.)

Amount of delivery from measuring 17.5 each pump (g/min.)

Orifice diameter (mm d 0.3

Number 7 Take-up velocity (tn/min.) 700 Drawing velocity (m/rnin.) 500Drawing ratio (.r) 3.5

TABLE 3.

Properties of Filament Size (d/filament) 128/7 Unevenness of side offilament 1.7 Strength (g/d) 5.32 Elongation 29.6 Crim ability 62.3 Loadvalue for 50% shrinkage (mg/d) 0.29

The filament spun in the above described operation conditions had nobending phenomenon immediately after spinning, so that it did not adhereto the spinneret surface and was produced very efficiently and moreover,the filament was not broken in the drawing and the degree of unevennesswas highly excellent.

The melt viscosity at 280 C of Nylon 66 chip used in the spinning was620 poises and the melt viscosity at 260 C of Nylon 6 Chip 580 poisesand it was ascertained that each melt viscosity in spinning of the bothpolymers was very near.

When the both polymers were spun at 280 C of the temperature inspinneret surface by means of a known conjugate spinning spinneret, thefilament deviated by 45 from the line perpendicular to the spinneretsurface immediately after spinning and the unevenness of size of theresulting filament was 4.9 percent.

EXAMPLE 2 Polycapramide (Nylon 66) having melt viscosity at 250 C of 440poises and polyhexamethylene sebacamide (Nylon 6.10, melting point 225C) having melt viscosity at 260 C of 1,480 poises were conjugate spunside by side in a conjugate ratio of 1:1 by using a conventionalspinneret. In this case, the temperature of spinneret surface was set at250 C, however, the difference of melt viscosities of the above polymerswas large, so that the filament bent considerably to Nylon 6.10 sideimmediately after spinning and finally adhered to spinneret surface, sothat the filament could not be formed.

Then, the same conjugate spinning was effected by using the samespinneret as described in Example 1. The operation conditions were shownin Tables 4 and 5 and the properties of the resulting filament wereshown in Table 6,

TABLE 4.

Heating Condition (C.)

TABLE 5.

Spinning and Drawing condition An amount of delivery from 12 eachmeasuring pump (g/min.) Orifice diameter (mmtp) 0.3

Number 18 Take-up velocity (rn/min.) 995 Drawing velocity (m/min.) 500Drawing ratio (x) 3.41

TABLE 6.

Properties of Filament Size (d/filament) 69.5 Unevenness of size offilament 2.0 Strength (g/d) 4.84 Elongation 31.6 Crimpability 69.5 Loadvalue for 50% shrinkage (mg/d) 0.365

By spinning under such a condition the bending phenomenon of thefilament was considerably improved as compared with the case using theabove described conventional spinneret and even if the take-up velocitywas increased to 995 m/min. even composite filament could be obtainedwithout causing any defects. Both the crimpability of the developedcrimp and crimp elasticity expressed by load value for 50 percentshrinkage showed excellent values. It has been ascertained that the meltviscosity at extrusion temperature of Nylon 6.10 was 550 poises.

EXAMPLE 3 Polycapramide having melt viscosity at 250 C of 2,900 poisesand polyethylene having high density (melting point C) having meltviscosity at C of 2,100 poises were melted separately by two meltingextruders and the molten polymers was conjugate spun by using thespinneret shown in FIG. 5 in such a manner that polycapramide wassurrounded by polyethylene in an eccentric core and sheath relation.

Said polymers were spun by means of a well known type of spinneret andby setting the temperature of spinneret surface at 240 C, but the spunfilament was considerably bent and the spinning could not be effected.

The operation conditions in spinning by means of the spinneret shown inFIG. 5 and the results are shown in Tables 7 to 9.

TABLE 8.

Spinning and Drawing Condition An amount of delivery from 49 eachmeasuring pump (glmin.)

Orifice diameter (mm 0.5

number 18 Take-up velocity (m/min.) 700 Dry heat drawing Drawingvelocity (m/min.) 300 Drawing ratio (x) 5.0 Drawing temperature (C) 60TABLE 9.

Properties of Filament Size (dlfilament) 248.4/18 Unevenness of size offilament 2.4 Strength (g/d) 5.7 Elongation 28 Crimpability 57 Load valuefor 50% shrinkage (mg/d) 0.25

When the spinning was started, some bending phenomena of the filamentwere observed, but the spinning and drawing operations were carried outsmoothly and the resulting filament had excellent evenness. The meltviscosities at the extrusion temperature of Nylon 66 and polyethylenewere 720 poises and 1,280 poises respectively.

EXAMPLE 4 The melt viscosities at various temperatures of polycapramidehaving intrinsic viscosity of 0.96 were determined and the results areshown in Table 10.

TABLE Temperature C. Melt viscosity (poises) Polyethylene terephthalatehaving melt viscosity of 820 poises at 285 C and said polycapramide wereconjugate spun by using the spinneret as used in Example 3 throughorifice of 0.3 mm d) X 18 holes in a conjugate ratio of 1:1 in such amanner that said polycapramide was surrounded eccentrically by saidpolyethylene terephthalate. The temperature of spinning polycapramidewas varied by adjusting the temperature in two Dowtherm jackssurrounding the spinneret and the spinnability was observed. Thetemperature of spinning polyethylene terephthalate was kept at 285 C.The taken-up composite filament was further drawn by 3.8 times indrawing velocity of 500 m/min. at 80 C and the drawn filament wasdetermined with respect to unevenness of size of filament. The obtainedresult is shown in Table l 1.

25, break did not occur, spinnability is good and takeup velocity was900 m/min. 2.4%

EXAMPLE 5 Polycapramide having a high degree of polymerization and meltviscosity at 250 C of 3,200 poises and polycapramide/polyhexamethyleneadipamide copolymer (copolymerization ratio 10 by weight, melting point:C) having melt viscosity at 225 C of 640 poises were conjugate spun in aside by side type by using the same spinneret as used in Example 1 in aconjugate ratio of 1:]. In the spinneret used, l8 holes, each diameterof which is 0.3 mm :15, were arranged in distance of 3 mm.

When the temperature of the spinneret surface in homopolyamide side wasset at 270 C and that in copolyamide side was set at 225 C, the meltextruded from the orifice bent considerably to homopolyamide side, whilefilament was formed, but the resulting filament adhered sometimes withadjacent melt in filament state.

When the temperature of the spinneret surface in homopolyamide was setat 290 C and that in copolyamide was set at 225 C, the compositefilament could be obtained efficiently without adhering or contactingwith adjacent filamentary melts. The resulting undrawn filaments weredrawn at a drawing velocity of 500 m/min., at room temperature by 38times to obtain drawn yarn of 70 deniers/lS filaments. The

property of said filament shown in Table 12.

TABLE 12.

Properties of Filament Temperature for Unevenness spinning homoof sizeof Conjugate form polyarnide filament 270 4.8 Unifonnity was observed inthe conjugated line 290 2.0 The conjugated line is substantiallystraight and uniform Cross section and vertical section of the filamentwere observed by polarization microscope.

EXAMPLE 6 Polyethylene terephthalate (polyester) having melt viscosityat 285 C of 2,200 poises and melt viscosity at 290 C of 1,800 poises andpolyethylene-p-oxybenzoate (polyester ether, melting point 220 C) havingmelt viscosity at 255 C of 1,700 poises (melt viscosity at 285 C of 900poises were conjugate spun in a side by side type by means of thespinneret described in Example 1 in a conjugate ratio of 1:1. Thetemperature condition, the spinning and drawing condition and theproperties of filament are shown in Tables 13 to 15 respec- TABLE 14.

Spinning and Drawing Condition Extruded amount (g/min.) 17.5 eachSpinneret used diameter (mm qb) 0.3

number 18 Take-up velocity (m/min.) 600 Drawing ratio (x) 4.07 Drawingtemperature ("C) 100 Drawing velocity 87 TABLE 15.

Properties of Filament Size (d/filament) 136.8/18 Strength (g/d) 4.30Elongation 49.83 Youngs Modulus (g/d) 31.59 Crimpability (70) 73.7 Loadvalue for 50% shrinkage (mg/d) 0.22 Unevenness of size of filament 1.8

The spinning was carried out very smoothly and the filament hadsatisfactory evenness. When said polymers were conjugate spun at 285 Cby means of a well known spinneret, the bending phenomena immediatelyafter spinning was very much and satisfactory spinning operation can notbe carried out.

EXAMPLE 7 Polycapramide chip having intrinsic viscosity of 0.95 afterwashed with water and dried, had melt viscosity at 250 C of 850 poises.The same chip which was not washed with water (monomer content, 9.5percent by weight) had melt viscosity at the same temperature of 320poises. The both polymers were conjugate spun in side by side type bymeans of the spinneret as described in Example 1 at a conjugate ratio of1:1. The spinneret was connected to two fire grid type meltingapparatuses. The heating condition, the spinning condition and theproperty of filament are shown in Tables 16 to 18, respectively.

TABLE 16.

Heating Conditions (C.)

Spinning and Drawing Condition Extruded amount (g/min.) 17.5 eachSpinneret diameter (mm 4:) 0.25

number 18 Take-up velocity (m/min.) 600 Drawing ratio (1:) 3.5 Drawingvelocity (m/min.) 500 TABLE l8.

Properties of Filament Size (d/filarnent) 163/18 Strength (g/d) 5.83Elongation 38.25 Crimpability 78.5 Load value for 50% shrinkage (mg/d)0.35 Unevenness of size of filament 1.83

Although said polymers were extruded through a well known spinneret forconjugate spinning at a temperature of 260 to 270 C, the extrudedpolymers adhered to the spinneret surface and the spinning could not becarried out.

What is claimed is:

1. A spinneret for producing a composite filament, which comprises afilter block provided with two solution reservoirs connecting toseparate tubes for transferring the spinning solutions, a nozzle plateprovided with at least one orifice, a breaker plate provided betweensaid filter block and said nozzle plate and provided with two channelsto introduce two spinning solutions from said solutions reservoirs tothe rear of the same orifice separately, heating means for controllingtemperature of two kinds of spinning solutions separately which surroundthe filter block, the breaker plate, and the nozzle plate, and heatinsulating means for preventing transmission of heat between thespinning solutions.

2. A spinneret as claimed in claim 1, wherein the means for controllingtemperature are jackets to heat each half spinneret divided into twoparts by heat insulating means independently from the outside, in whichheating media are circulated.

3. A spinneret as claimed in claim 2, wherein the means for controllingtemperature are electric heaters to heat each half spinneret dividedinto two parts by heat insulation means independently from the outside.

4. A spinneret for producing a composite filament, which comprises afilter block provided with two melt reservoirs connecting to separatetubes for transferring the spinning melts. a nozzle plate provided withat least one orifice, a distributor plate provided between said filterblock and said nozzle plate and provided with two channels to introducetwo spinning melts from said melt reservoirs to the rear of the sameorifice separately, means for controlling the temperatures of the twospinning melts separately which surround the filter block. the breakerplate, and the nozzle plate, and heat insulating means for retardingtransmission of heat between the spinning melts.

5. A spinneret as claimed in claim 4, wherein the heat insulating meansinclude heat insulators provided between the two melt reservoirs.

6. A spinneret as claimed in claim 4, wherein at least one row ofventilating holes are provided in the heat insulator.

7. A spinneret as claimed in claim 4, wherein the means for controllingtemperature are electric heaters to heat each half spinneret.

i i l 1

2. A spinneret as claimed in claim 1, wherein the means for controllingtemperature are jackets to heat each half spinneret divided into twoparts by heat insulating means independently from the outside, in whichheating media are circulated.
 3. A spinneret as claimed in claim 2,wherein the means for controlling temperature are electric heaters toheat each half spinneret divided into two parts by heat insulation meansindependently from the outside.
 4. A spinneret for producing a compositefilament, which comprises a filter block provided with two meltreservoirs connecting to separate tubes for transferring the spinningmelts, a nozzle plate provided with at least one orifice, a distributorplate provided between said filter block and said nozzle plate andprovided with two channels to introduce two spinning melts from saidmelt reservoirs to the rear of the same orifice separately, means forcontrolling the temperatures of the two spinning melts separately whichsurround the filter block, the breaker plate, and the nozzle plate, andheat insulating means for retarding transmission of heat between thespinning melts.
 5. A spinneret as claimed in claim 4, wherein the heatinsulating means include heat insulators provided between the two meltreservoirs.
 6. A spinneret as claimed in claim 4, wherein at least onerow of ventilating holes are provided in the heat insulator.
 7. Aspinneret as claimed in claim 4, wherein the means for controllingtemperature are electric heaters to heat each half spinneret.